Nov. 9An international review of a controversy over bioengineered genes in Mexican corn recommends that Mexico combat the biotech intrusion by requiring labeling or milling of kernels imported from countries such as the United States.

The suggestion, made by a panel of scientists advising the Commission for Environmental Cooperation of North America, was not welcomed by the U.S. government, which offered harsh words after the report's official release on Monday.

"This report is fundamentally flawed and unscientific," said a statement issued by the U.S. Environmental Protection Agency.

"The authors acknowledge that no economic analysis of their recommendations was conducted, and that many of these recommendations are based solely on sociocultural considerations," the EPA complained.

The environmental commission was set up under the North American Free Trade Agreement and is composed of the heads of the environmental protection agencies in Canada, Mexico and the United States. None of the countries is obligated to adopt the recommendations. But objections by one country can't stop another country from acting.

A statement by the Mexican government last month in anticipation of the report's official release was much more receptive.

"There is no doubt that the recommendations ... will be beneficial for Mexico and its environment," a translated version of the response states.

The report and reaction reflect long-standing, sharply divided world opinions over the value and risks of agricultural biotechnology. The technology enables scientists to insert genes into plants and animals in ways not possible in nature.

The United States leads the world in introducing and adopting genetically engineered crops. Federal policy and industry similarly emphasize biotech's potential benefits, such as reducing reliance on chemical pesticides.

But countries in other parts of the world  most notably Europe and Japan  are concerned that the technology will cause environmental problems, such as the development of superweeds, or harm consumers' health.

In 2001, scientists at the University of California, Berkeley, reported that they had discovered biotech genes in cornfields cultivated by indigenous farmers in Oaxaca, Mexico. The finding caused an international storm because it was viewed as evidence that the technology was out of control.

The discovery was all the more provocative because at the time, cultivating biotech corn in Mexico was illegal. (Limited experimental cultivation has since been authorized.) Like wheat in the United States, corn is the basis of many foods in Mexico. As such, it is given special consideration in that country.

The finding also had ramifications for the United States, because it's generally believed that the biotech genes originated from American grain imports.

Though the imports are intended as food, indigenous farmers often experimentally plant kernels they buy at the store.

Outraged, Greenpeace Mexico, along with a coalition of Mexican people representing affected rural communities there, petitioned the Commission on Environmental Cooperation to undertake a review.

The commission assembled a diverse team of scientists to produce the report. Among them was Norman Ellstrand, a geneticist at UC Riverside and an international authority on "gene flow" in plants  the movement of genes from organism to organism, be it by pollen dissemination, manipulation by people or other means.

Ellstrand said biotech genes, or "transgenes," do not travel in nature any more readily than naturally occurring genes. Still, the panel felt that the Mexican government should be allowed to evaluate the impact of the technology on its crop, just as the U.S. government now evaluates each biotech food crop before it is "deregulated" for release in this country.

"It's presumptuous to think that just because they've been deregulated here, it's OK there," Ellstrand said.

"What if there were transgenic seeds that the United States was receiving that had been deregulated in Cuba and not in the United States?" he asked. "How would the United States feel about that?"

The EPA singled out the suggestion to mill the corn as particularly onerous.

Such a requirement "would increase the cost of U.S. corn significantly, negatively affecting Mexico's livestock producers and consumers," states a letter to the commission from Judith Ayres, assistant administrator in the EPA's Office of International Affairs.

"Furthermore, the report does not consider logistical considerations, such as whether it is, indeed, feasible to mill at border facilities the roughly 6 million tons of maize that Mexico imports annually."

The response does not address the recommendation of labeling U.S. imports as potentially containing biotech genes, but federal policy has consistently opposed labeling, as well.